Concentración de bupivacaína y preservación de fuerza de cuádriceps en bloqueo femoral para artroplastía total de rodilla / Bupivacaine concentration and quadriceps strength preservation in femoral nerve block for total

INTRODUCTION: The commonly used concentrations of local anesthetics (LA) for femoral nerve block (FNB) cause a significant decrease in the quadriceps strength (QS), limiting physiotherapy and determining a risk factor for patient's falls. The use of more dilute solutions could determine the preservation of motor function without impairing analgesia. METHODS: Five patients scheduled for total knee arthroplasty (TKA) received a preoperative FNB with 20 mL of bupivacaine in decreasing concentrations (0.0875%, 0.075%, 0.0625%, 0.050%, 0.0375%). Sensory block to cold in the anterior knee region, QS, surface electromyography (SEMG) of vastus lateralis (VL), vastus medialis (VM) and rectus femoris (RF) plus were recorded before and 30 minutes after the blockage. Posteriorly, the clinical data of 20 patients who underwent TKA and received a continuous femoral nerve block (CFNB) with bupivacaine in the most dilute concentration that granted sensory blockade and significantly preserved the QS in the previous analysis were retrospectively analyzed. Postoperative pain at 24 and 48 hours, morphine consumption at 24 hours, the ability to successfully perform physiotherapy on the first postoperative day (POD) and reports of falls were rescued from the patients' files. Finally, seventy-five patients that underwent TKA during 2018 who received a CFNB with a similar dilution, but using levobupivacaine, were also retrospectively analyzed. Postoperative pain, need for advanced rescue analgesia, ability to perform physiotherapy, CFNB related complications and reports of patients falls during the first 72 hours post-surgery were obtained. RESULTS: Biomechanical study: of the 5 concentrations analyzed, either 0.050% or 0.0375% bupivacaine were adequate producing sensory block and preserving 94% and 100% of the basal QS, respectively. With both concentrations, the SEMG showed a similar range of activation with respect to baseline values. Bupivacaine case series: Twenty patients undergoing TKA received a 5-8 mL/hr infusion of 0.037% bupivacaine. The average consumption of morphine at 24 hours was 3.9 (3.6) mg. The median [IQR] of dynamic postoperative pain at 24 and 48 hours was 3 [1-4] and 3 [2-5]. All patients had adequate active joint ranges at 24 hours and physiotherapy was not limited by significant motor block. No falls were reported during the stay. Levobupivacaine case series: seventy-five patients undergoing TKA received a 5-8 mL/hr infusion of 0.037% levobupivacaine. The median [IQR] of at rest (R) and dynamic (D) postoperative pain at 24, 48 and 72 hours were R24: 0 [0-3]; D24: 3 [1-5]; R48: 0 [0-2]; D48: 3 [1.5-5]; R72: 0 [0-1]; D72: 3 [1-4]. 21% of patients required adding a PCA mode to the CFNB and a 7% a morphine PCA. On POD 1, 4% of patients were not able to adequately perform rehabilitation. On POD 2 and 3, all patients had adequate active joint ranges and physiotherapy was not limited by significant motor block. There were also no falls during hospitalization. CONCLUSIONS: The use of diluted solutions of bupivacaine and levobupivacaine for CFNB may represent a good alternative for TKA postoperative analgesia while avoiding significant quadriceps paresis. Additional studies are necessary to determine the ideal concentration and administration regimen to then compare with other quadriceps sparing analgesic alternatives.

INTRODUCCIÓN: Las concentraciones habituales de anestésicos locales (AL) utilizadas para el bloqueo del nervio femoral (BNF) provocan una disminución significativa de la fuerza del cuádriceps (FC), limitando la fisioterapia y constituyendo un factor de riesgo de caídas de pacientes. El uso de soluciones más diluidas podría determinar preservación de la función motora sin perjudicar la analgesia. MÉTODOS: Cinco pacientes programados para artroplastía total de rodilla (ATR) recibieron un BNF preoperatorio con 20 mL de bupivacaína en concentraciones decrecientes (0,0875%, 0,075%, 0,0625%, 0,050%, 0,0375%). Se registró la FC, electromiografía de superficie (EMGS) de vasto lateral (VL), vasto medial (VM) y recto femoral (RF) y el bloqueo sensitivo al frío antes y 30 minutos después del bloqueo. Posteriormente, se analizó retrospectivamente 20 casos sometidos a ATR que recibieron un bloqueo continuo del nervio femoral (BCNF) con bupivacaína en la concentración más diluida que otorgó bloqueo sensitivo y preservó significativamente la fuerza basal del cuádriceps durante el análisis anterior. El dolor postoperatorio a las 24 y 48 horas, el consumo de morfina las primeras 24 horas, la capacidad de realizar con éxito la fisioterapia el primer día postoperatorio (DPO) y reporte de caídas fueron rescatados de los expedientes. Por último, también se analizó retrospectivamente un grupo de 75 pacientes sometidos a ATR durante el 2018 y que recibieron un BCNF con una dilución similar, pero de levobupivacaína. Se obtuvieron datos de dolor, requerimientos de rescate analgésico, capacidad de realizar rehabilitación, complicaciones del BCNF y reporte de caídas durante las primeras 72 horas postoperatorias. RESULTADOS: Estudio biomecánico: de las 5 concentraciones analizadas, tanto bupivacaína 0,05% como 0,0375% produjeron adecuado bloqueo sensorial preservando el 94% y el 100% de la FC, respectivamente. Con ambas concentraciones la EMGS mostró similar rango de activación respecto a valores basales. Serie de casos con bupivacaína: veinte pacientes sometidos a ATR recibieron una infusión de bupivacaína 0,037% a 5-8 mL/h. El consumo promedio de morfina a las 24 horas fue 3,9 (3,6) mg. La mediana [RIC] del dolor dinámico postoperatorio a las 24 y 48 horas fue 3 [1-4] y 3 [2-5]. Todos los pacientes tuvieron rangos articulares activos adecuados a las 24 horas y la fisioterapia no fue limitada por bloqueo motor significativo. No se registraron caídas durante la hospitalización. Serie de casos levobupivacaína: setenta y cinco pacientes sometidos a ATR recibieron una infusión de levobupivacaína 0,037% a 5-8 mL/h. La mediana [RIC] de dolor postoperatorio en reposo (R) y dinámico (D) a las 24, 48 y 72 horas fue R24: 0 [0-3]; D24: 3 [1-5]; R48: 0 [0-2]; D48: 3 [1.5-5]; R72: 0 [0-1]; D72: 3 [1-4]. Un 21% requirió agregar modo PCA al BCNF y 7% una PCA de morfina. En DPO 1, un 4% de pacientes no pudo realizar adecuadamente la rehabilitación. En DPO 2 y 3 todos los pacientes tuvieron rangos articulares activos adecuados y fisioterapia no fue limitada por bloqueo motor significativo. Tampoco se registraron caídas durante la hospitalización. CONCLUSIONES: El uso de soluciones diluidas de bupivacaína y levobupivacaína en BCNF podría representar una buena opción para analgesia postoperatoria en ATR evitando la paresia significativa del cuádriceps. Estudios adicionales son necesarios para determinar la concentración y régimen de administración ideal para luego comparar con otras alternativas analgésicas preservantes del cuádriceps.

Differences in knee sensorimotor control by physical activity level and sex / Diferenças no controle sensorimotor do joelho por nível atividade física e sexo

ABSTRACT Objective: The aim of this study was to compare the differences in knee sensorimotor control between healthy men and women by measuring the joint position sense (JPS), sensation of muscle tension (steadiness), and onset of muscle activation (OMA). Methods: Twenty-four healthy women and 27 healthy men were tested. Knee sensorimotor control was assessed using the JPS test with electrogoniometers in 3 different ranges of motion, sensation of muscle tension using the isometric steadiness technique, and OMA against a mechanical perturbation. Each assessment was compared by sex, physical activity level, and right or left lower limb. Results: The men obtained better values in the JPS test between 90º and 60º and between 30º and 0º than the women. The subjects with higher levels of physical activity also showed better values, between 90º and 60º and between 30º and 0º. The best results for steadiness were found in the women and the subjects with higher levels of physical activity. In the OMA test, no significant differences were found in the studied variables. Conclusion: The results suggest that higher levels of physical activity may determine better sensorimotor control. Men have better articular sensation, and women have better muscle strength control. Level of evidence III, Cross sectional study.

RESUMO Objetivo: O objetivo desse estudo foi comparar as diferenças no controle sensório-motor de joelho entre mulheres e homens saudáveis medindo o sensação da posição articular (SPA), Coeficiente de variações da força (Steadiness) e inicio ou ativação muscular (IAM) Métodos: Foi avaliado 24 mulheres saudáveis e 27 homens saudáveis, realizando avaliações de SPA, o Sensação de tensão muscular (Steadiness) e o IAM, comparadas segundo sexo, nível de atividade física e extremidades inferiores direita ou esquerda. Resultados: SPA: Os homens obtiveram melhores valores nessa prova entre 90-60° (p=0,0127) e em 30-0° (p=0,0017) ao comparado com as mulheres. as pessoas com maior nível de atividade física também se encontram melhores resultados entre 90-60° (p=0,0328) e 30-0° (p=0,0173). STEADINESS: Os melhores resultados foram para as mulheres em ambas extremidades (direita p=0,0002 e esquerda p=0,0009) e pessoas com maior nível de atividade física (direita p=0,0065 e esquerda p=0,0173). Para IAM não foi encontrado diferenças significativas nas variáveis estudadas. Conclusão: Os resultados sugerem que tanto maior nível de atividade física puderam determinar maior resultado no controle sensório-motor. Os homens tiveram maior sensação articular e as mulheres maior controle steadiness. Nível de evidência III, Estudo transversal.